BTN3A1 and neoplasm: As mentioned earlier, agonistic mAbs directed against BTN3A1/CD277, such as clone 20.1, are very potent and selective activators of Vδ2T cells.25,31 BTN3A1 is expressed on tumor cells,192 and sensitizing tumor cells with an anti-BTN3A1 mAb drastically increases sensitivity to γδ T cell killing.31 Therefore, a novel strategy for in vivo activation of tumor-reactive Vδ2 T cells is the therapeutic application of a humanized anti-BTN3A1 mAb.